Saturday, April 14, 2012

Study : The Extreme Male Brain Theory of Autism Revisted

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The extreme male brain theory of autism is the idea that many of the traits of autism can be looked at as extreme versions of traits that are common in men.  Autism could then be "caused" by something that takes an ordinary brain and then turns up the male features of the brain and turning down the female features.

Or something like that.

To be honest, I have never really liked the theory.  Maybe that is because I have daughters with autism or maybe it is because I don't buy into the stereotypes of what men are supposed to be like.

Or, just maybe, it is because there is very little data to support the theory.  It is one thing to look at some high-function people with autism and come up with a theory of how they think but it quite another to actually have real data that supports the theory.  And no, 2D:4D finger ratios and preferred hip-waist ratios don't count as real data.

Regardless, I found this study that was just published to be rather informative and funny at the same time.  The abstract is below.
BACKGROUND: The 'extreme male brain' theory suggests that autism spectrum disorder (ASD) is an extreme variant of male intelligence. However, somewhat paradoxically, many individuals with ASD display androgynous physical features regardless of gender.
AIMS: To assess physical measures, supposedly related to androgen influence, in adults with and without ASD.
METHOD: Serum hormone levels, anthropometry, the ratio of 2nd to 4th digit length (2D:4D) and psychiatric symptomatology were measured in 50 adults with high-functioning ASD and age- and gender-matched neurotypical controls. Photographs of face and body, as well as voice recordings, were obtained and assessed with respect to gender coherence, blindly and independently, by eight assessors. 
RESULTS: Women with ASD had higher total and bioactive testosterone levels, less feminine facial features and a larger head circumference than female controls. Men in the ASD group were assessed as having less masculine body characteristics and voice quality, and displayed higher (i.e. less masculine) 2D:4D ratios, but similar testosterone levels to controls. Androgynous facial features correlated strongly and positively with autistic traits measured with the Autism-Spectrum Quotient in the total sample. In males and females with ASD dehydroepiandrosterone sulfate did not decrease with age, in contrast to the control group. 
CONCLUSIONS: Women with ASD had elevated testosterone levels and several masculinised characteristics compared with controls, whereas men with ASD displayed several feminised characteristics. Our findings suggest that ASD, rather than being characterised by masculinisation in both genders, may constitute a gender defiant disorder.
So now, instead of autism being "characterised by masculinisation in both genders", it is now suggested that it "may constitute a gender defiant disorder"...

Really?   It was bad enough to suggest that autism was just being too masculine.  Do we really want to another theory that suggests that autism is all about gender ambiguity?  I'm sure that will go over well.

And what about the non-"high functioning" people with autism, otherwise known as the majority of people with autism, why are they excluded - yet once again - from a study like this?  If you are trying to test the validity of a theory of autism spectrum disorders perhaps it would be beneficial to test it against the majority of people with autism.

But, on a more serious note, there are two bits in the abstract that are interesting and both speak to an ongoing biological process.

First, why would the women with autism have a higher level of testosterone and what exact process would cause a women's testosterone level to remain elevated throughout her life?

Second, why would older males and females with autism have a higher level of dehydroepiandrosterone sulfate than the controls?  My knowledge is more than a little lacking in this area, but from what I understand the body uses steroid hormones like this to help control metabolism, inflammation, immune function, as well as other things.  This particular steriod hormone can be converted into testosterone and estrogens and also might be able to control neuronal excitability and gene expression.

Or in other words, having an unusual level of this substance suggests that there is something going on that the body is trying to control.  Since most of the things on the list above are impacted in autism, might not this be something to focus on?

It is all well and good to have yet another study (34 and counting) that looks at what is basically idle speculation,  but wouldn't it be better to spend the research dollars investigating actual biological differences in people with autism and trying to find their source?

References

Bejerot S, Eriksson JM, Bonde S, Carlström K, Humble MB, Eriksson E. The extreme male brain revisited: gender coherence in adults with autism spectrum disorder. Br J Psychiatry. 2012 Apr 12. [Epub ahead of print]  PubMed PMID: 22500012.  DOI: bjp.bp.111.097899

11 comments:

  1. Re 'wouldn't it be better to spend the research dollars investigating actual biological differences in people with autism and trying to find their source?'

    Amen to that!

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  2. The reason why autistic men have to look feminine, elfin, or childlike is simple and quite nasty.

    Autistic guys make social mistakes. If you don't have the right look, forgiveness is not forthcoming, and one's reproductive chances are diminished. Autistic blokes who look manly are much more threatening and therefore much more likely to have been brutalised by folk in the past.

    It's different for girls, obviously.

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  3. I don't understand why so many otherwise respectable brain science people are so keen to propose simplistic models - usually just analogies or extended metaphors - and then try to fit the small amount of data to them. It's shameful. Though I actually do understand it: if your model turns out to be the right one, you get to be The Main Man. For nonautistics, even supposed scientists, that is important.

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  4. I'm not a "fan" of the extreme-male theory either. It is superficially attractive when you're first learning about autism, particularly because "male" is something we think we understand, so comparing autism to extreme maleness makes the hard-to-understand seem accessible. From what I've read too, there aren't particularly impressive grounds for holding onto the theory.

    Interesting post, I enjoy reading your opinions and break-downs of autism studies, always provides something further to ponder.

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  5. Re 'wouldn't it be better to spend the research dollars investigating actual biological differences in people with autism and trying to find their source?'
    Amen to that!

    Interesting post, I enjoy reading your opinions and break-downs of autism studies, always provides something further to ponder.
    Amen to that!

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  6. You can debate all the research and opinion you want but facts are stubborn things. Here are a few facts:

    My adult son with autism (age 21) is 6'5", weighs 250 lbs, grows beards in a day, is inappropriate sexually, can be terrifyingly aggressive. Whether you think there is a link or not, something is wrong with this man's level of hormones.

    I don't give a hoot about mercury or fetal exposure, who cares, what I do know is that something is wrong with his hormones, could we possibly just take a look at that one simple thing?

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    Replies
    1. I don't think we are actually disagreeing on anything here.

      I completely agree that there are many biological imbalances, including horomonal imbalances, in children and adults with autism that need to be investigated.

      But, and this is a rather large but, the "extreme male brain theory" of autism suggests that exposure to higher than normal levels of testosterone during critical prenatal periods is what can cause autism. It doesn't really say whether you should expect to see a continuing higher level of testosterone later in life.

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  7. 'First, why would the women with autism have a higher level of testosterone and what exact process would cause a women's testosterone level to remain elevated throughout her life'?

    An interesting question. All human neonates during the first year of life undergo what is known as the 'neonatal testosterone surge' During the surge, increased production of testosterone occurs, higher in males than in females.

    Birth aspyxia is a known autism risk factor. Induced birth aspyxia (global birth hypoxia)in mice produced increased levels of testosterone production during the neonatal testerone surge in male and female mice. Over time the testostorone surge subsides and testosterone production tends to normalize. When normalization occurs measuring testosterone levels in puberty, adolescence and in adults may be uninformative.

    General population studies that apply Baron-Cohen's AQ scores indexed by Apgar scores is warrented. I have a paper under peer review exploring this very topic.


    References

    Boksa P, Zhang Y. (2008). Global birth hypoxia increases the neonatal testosterone surge in the rat. Neuroendocrinology.88(4):266-75.

    http://www.ncbi.nlm.nih.gov/pubmed/18594128

    Jensen RA (2012). Brief Report: Klinefelter Syndrome and XYY Syndrome: The extreme male brain theory of autism and the role of early testosterone production in brain development and behavior. Under review.

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  8. Ever met a fighter pilot or elite racing driver? They are typically monosyllabic, extremely individualistic, hyper-aggressive and almost invariably have thick beards and very prominent chins (signs of high testosterone levels).

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  9. It is not possible to understand causes of autism spectrum disorders without knowing the functional components of brain that form mind.

    Just four functional components of Dichotomized Operating System model of mind with their fixed characteristics single-handedly explain causal mechanisms of all major symptoms of Autism Spectrum Disorders, available here http://www.whatismind.com/DFAAA.aspx.

    ReplyDelete